1. Field of the Invention
This invention relates generally to a redundant d.c. power supply arrangement for supplying power to a load circuit and means for protecting the power supply arrangement from voltage transients of high frequency and magnitude which emanate from the load circuit.
2. Background of the Prior Art
It is known to connect redundant d.c. power supplies in electrical parallel for supplying power to a single load. Since the voltages of the power supplies are generally not identical, it is known to place an auctioneering diode in series with each power supply. In such an arrangement the diode associated with the power supply having the highest voltage magnitude will be forward biased, connecting its power supply to the load. The diode associated with the power supply having the lower voltage magnitude will be back biased by the higher voltage magnitude of the other voltage supply, effectively taking the power supply of lower voltage magnitude out of the circuit. Such an arrangement also prevents the power supply having the lower voltage magnitude from being short-circuited by the other power supply. If either one of the power supplies is physically removed from the circuit or is otherwise rendered inoperative, the other voltage supply in such a redundant arrangement will supply the power to the load.
A problem arises with this type of redundant voltage supply arrangement when it is used to supply power to a load circuit which has components in it or coupled to it which can generate a voltage transient of high frequency and magnitude in the load circuit. Such a voltage transient would likely burn out the series connected diodes associated with the redundant power supplies, resulting in a disconnection of the power supplies from the load circuit.